Thomas Mercer, England, c. 1970's. 7"h x 4.5"diameter -
movement, 8" x 8". Model of John Arnold style spring detent
escapement. Bi-metallic balance temperature compensation. Two hour duration. Mercer
had made few of these models, probably less than 10 in the 1970's. Some had damascened
plates, some polished as in this example.